Wifi-Hal: Avoid sending RTT request when RTT feature is disabled

Driver controls reporting of wihpy supported features
(WIFI_FEATURE_D2AP_RTT /  WIFI_FEATURE_D2D_RTT)
usnig ini(gEnableRTTSupport). But wifihal send down
the request without verifying whether features is supported
by driver or not.

As a part of fix, ensure rtt feature is supporetd by driver
in wifihal.

Change-Id: I7ffe0a690cf11b6f33580542648707cd5e7cbd59
CRs-Fixed: 2565215